I posted this in the engine forum too, just trying to get some ideas.

I got my bike 3 years ago new from a dealer. Every now and then I find a small oil spot on the floor under the swing arm on the left side. Now there is a vent tube directly above the spot, right in front of the mudguard, but it runs to the gas tank. When I first got the bike, I kind of freaked about it and had a couple dealers look at it. None found a leak, and I have since read on this forum that this is not uncommon on softails if the oil level rises or if the oil tank is overfilled. It has not done it in a long time, but after riding yesterday, I found another small spot. I know my oil level isn't overfilled. I actually keep it at the 3/4 (when hot) to prevent oil in the air filter, etc.

I dont' think it's leaking, b/c there is no oil trail. It's like it is puking it out of a vent or something?

Any ideas?

I've never noticed a drop in oil level or anything like that.

Oil Spot

Vent Hose

 

i had a spot underneath our golf cart. couldn't figure it out until it got into a cut on my finger. wasn't oil. battery acid. kids had wrecked it and busted a small hole in the battery. they are hard to trace for sure.

 

3 words... It's a Harley.

 

That's the spot on mine where the drain plug for the oil tank is. Maybe the O-ring on your drainplug went bad?

 

There is an overflow line in that area for the tranny.
See if you can find it on top in the rear of the tranny and follow it down the back of the tranny.
I'll lay odds that's where its coming from, but don't be too worried about it.
Whats probably happening is that the oil in the tranny is getting flung around while your riding and a little is hitting the overflow tube on top of the tranny.
Then when you stop is just drips a little. If its not doing any more than a few drops I wouldn't worry about it.
Its not going to loose enough to make any kind of measureable difference or be a problem. Bet your using Syn3 or another motor oil grade/weight oil in there.
If you change the oil for a heavier grade of oil like Mobile 1 75/90W or another comparable grade and it might slow it down or eliminate it altogether.

 

My drain plug is on the opposite (right) side of the swingarm. I'm going to put it up on the lift in a few minutes and see what I can see. I just washed it pretty good, so any oil residue should be visible...hopefully.

I know it's a Harley, but it's a little frustrating.

I think, Shovelhead Bob told me a couple years ago that this was normal. I can't find the PM to verify that though. It just hasn't done it in a while, so it's peaked my interest again.

 

I had a mysterious spot on my floor last summer.

It was -24 here today.

Turned out that the tranny drain plug was just a tad loose.

Just a thought.

MikeM

 

I'm actually using 75w90 Amsoil Severe Gear in the tranny. I'll check that first thing. Headed out to the garage now. thanks

 

Well, after 90 minutes of searching, I got nothing. I took off the mudguard, which was way easier than I expected and everything is as dry as a bone.

I could not find that tranny vent anywhere. If anyone can direct me further I would appreciate it. Tranny plug is tight. No residue anywhere. Guess I'll just ride it. Or I could sell it and buy a new one, LOL.

 

+1 on the trans vent. Unless you just changed it, that isn't engine oil.

It's not a surprise that a heavy weight oil would be found under the lowest part of the bike either. Regardless of where it came from gravity would work it along the frame until it couldn't go any lower. whenthe drop got heavy enough it drops. As clean as your bike is, it should be relatively easy to get on the ground and flashlight up and to the front. Any chance your wife or a buddy is trying to drive you nuts?